This invention relates generally to an encapsulated beam and method of encapsulating the beam. Particularly the invention relates to a device including a protecting material encapsulated metallic beam and method of encapsulating the metallic beam using the protecting material layer.
Microelectromechanical systems (MEMS) are electromechanical devices that generally range in size from a micrometer to a millimeter in a miniature sealed package. A MEMS device in the form of a microswitch has a movable electrode called a beam that is moved toward a stationary electrical contact by the influence of a gate electrode positioned near the beam. The movable electrode may be a flexible beam that bends under applied forces such as electrostatic attraction, magnetic attraction and repulsion, thermally induced mismatch that closes a gap between a free portion of the beam and the stationary contact. One form of a movable flexible beam is a cantilever beam. In another form the movable beam is fixed at two ends.
Introduction of contaminants such as moisture, particulates, or oxygen into the area surrounding the device can cause sticking, contamination, or interference of the metal contacts, leading to device failure. MEMS cantilever beams are often manufactured during the MEMS device formation by depositing the beam material and then releasing the beam material by dicing or etching out the layer below the beam structure. This dicing or etching procedure during manufacturing may lead to the device degradation during operation.
Therefore, methods of protecting the beam structure from attack and degradation during release and operation, preventing the device failure by particle generation and/or performance alteration are needed.